Morphology of Flowering Plants: Roots and Stems

A set of vocabulary flashcards detailing the structural morphology of roots and stems, including types of root systems and specialized regions.

Dicotyledonous plants

Plants where the direct elongation of the radicle leads to the formation of the $1^\circ$ root (primary root) which goes inside the soil.

Tap Root System

A root system consisting of a primary root and its lateral branches (secondary and tertiary roots), as seen in the mustard plant.

Fibrous Root System

A root system typical of monocots, such as the wheat plant, where the short-lived primary root is replaced by a large number of roots originating from the base of the stem.

Adventitious roots

Roots that arise from parts of the plant other than the radicle, found in plants like Monstera, Banyan, and Grass.

Main functions of the Root System

Absorption of $H_2O$ and minerals from soil, providing anchorage, storing reserve food materials, and synthesis of plant growth hormones.

Root Cap

A thimble-like structure that covers and protects the tender apex of the root.

Region of meristematic activity

The region a few millimeters above the root cap where cells are very small, thin-walled with dense cytoplasm, and divide repeatedly.

Region of elongation

The area proximal to the meristematic region where cells undergo rapid elongation and enlargement, leading to growth in length.

Region of maturation

The region proximal to the elongation area where cells differentiate and mature; this is the area where root hairs are formed.

Root hairs

Fine thread-like structures formed by epidermal cells in the region of maturation that increase surface area for the absorption of $H_2O$ and minerals.

Stem

The ascending part of the plant axis that develops from the plumule of the embryo of a germinating seed.

Nodes

The regions of the stem where leaves are born.

Internodes

The portions of the stem located between two nodes.

Plumule

The part of the embryo of a germinating seed from which the stem develops.

Functions of the Stem

Conducting $H_2O$, minerals, and photosynthates; spreading out branches; and occasionally performing storage, support (tendrils), protection (thorns), and vegetative propagation.